I think that link pretty much answers your question - he wants to work on his art and writing. He doesn't have to retire, but he wants to. Seems fair enough to me; I'm sure Hairspray alone means he's rich enough to afford it. And given his standard rate of production, it's going to be a few years before he finishes those two films anyway.

Like a wayward Santa for the Christmas obsessed, legendary filmmaker and raconteur John Waters rides into town on his sleigh full of smut this December spreading yuletide cheer with his critically acclaimed one-man show, "A John Waters Christmas".

Putting the "X"in Xmas, Waters rapid-fire monologue explores and explodes traditional archetypes as he shares his compulsive desire to give and receive perverted gifts, a religious fanaticism for Santa Claus, and an unhealthy love of true crime holiday horror stories. Delving into his passion for lunatic exploitation Christmas movies and the unhealthy urge to remake all his own films into seasonal children's classics, "The Pope of Trash"will give you a Joyeaux Noel like no other.

John Waters is the quintessence of cult films and the 'midnight movies' phenomenon, and his films--which range from Mondo Trasho, Pink Flamingos, and Female Trouble, via the original Hairspray that inspired the successful Broadway show of the same name, to A Dirty Shame and Cry Baby, the breakthrough-film of a tender-faced Johnny Depp, are eternal classics.